The present invention is directed to a pulp comprised of fibrils of thermotropic liquid crystal polymers.
Various articles such as papers comprised of polymeric materials have been employed for many purposes. For example, such structures have been employed as filters and electrical insulation, etc. However, such articles are frequently not appropriate for use in a high temperature environment (e.g., temperatures in excess of about 200.degree. C.) or in an environment where the structure will come into contact with corrosive chemicals or solvents. It is therefore desirable to provide articles comprised of a polymeric material which is resistant to solvents or corrosive chemicals and suitable for use at high temperatures.
It has been recently found that thermotropic liquid crystal polymers can be advantageously used in non-woven articles and papers to impart the desired thermal and chemical resistance thereto. See, for example, the above-referenced related U.S. Patent applications (1) and (2).
As noted in the above-referenced application (3), a pulp comprised of fibrils of thermotropic liquid crystal polymers can be provided by masticating various articles comprised of such polymers. While such articles can be broken up without too much difficulty due to the high degree of orientation of the polymer within the article, it has been found that a significant amount of time and energy is frequently required to provide a pulp comprised of submicron size particles (e.g., fibrils) of thermotropic liquid crystal polymers.
It is therefore desirable to provide a thermotropic liquid crystal polymer which can readily be broken up into submicron size particles to form a pulp suitable for use in articles such as papers.
It is also desirable to provide a method by which a thermotropic liquid crystal polymer can be readily broken up into submicron size particles to provide a pulp suitable for use in articles such as papers.
It is also known to those skilled in the art that the heat treatment of shaped articles of liquid crystal polymers increases the melting temperature, molecular weight and mechanical properties of the polymer. See, for example, U.S. Pat. Nos. 3,975,487; 4,183,895; and 4,247,514.